/**
* @author AlbertDarren
* @contact 2563491540@qq.com
*/
#include <iostream>
#include <string>
using namespace std;

int main_21()
{
    string qq="2563491540";
    string domain_name=".com";
    string::iterator iter=qq.end();
    qq.insert(iter,'@');
    cout << qq << endl;
    qq.insert(qq.end(),2,'q');
    cout << qq << endl;
    qq.insert(qq.end(),domain_name.begin(),domain_name.end());
    cout << qq << endl;
    qq.assign("albertdarren.");
    cout << qq << endl;
    qq.erase(--qq.end());
    cout << qq << endl;
    qq.erase(qq.begin()+6,qq.end());
    cout << qq << endl;
    qq.append("@");
    cout << qq << endl;
    qq.append(2,'q');
    cout << qq << endl;
    qq.insert(qq.size(),domain_name);
    cout << qq << endl;
	return 0;
}
